<?php

namespace Top\Security;

class Security
{

    private static $iv = "0102030405060708";

    public static function encrypt($input, $key)
    {
        $key = base64_decode($key);
        $localIV = Security::$iv;
        $module = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_CBC, $localIV);
        mcrypt_generic_init($module, $key, $localIV);
        $size = mcrypt_get_block_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC);
        $input = Security::pkcs5_pad($input, $size);
        $data = mcrypt_generic($module, $input);

        mcrypt_generic_deinit($module);
        mcrypt_module_close($module);
        $data = base64_encode($data);

        return $data;
    }

    public static function hmac_md5($input, $key)
    {
        $key = base64_decode($key);

        return hash_hmac('md5', $input, $key, true);
    }

    private static function pkcs5_pad($text, $blocksize)
    {
        $pad = $blocksize - (strlen($text) % $blocksize);

        return $text.str_repeat(chr($pad), $pad);
    }

    public static function decrypt($sStr, $key)
    {
        $key = base64_decode($key);
        $localIV = Security::$iv;
        $module = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_CBC, $localIV);
        mcrypt_generic_init($module, $key, $localIV);
        $encryptedData = base64_decode($sStr);
        $encryptedData = mdecrypt_generic($module, $encryptedData);

        $dec_s = strlen($encryptedData);
        $padding = ord($encryptedData[$dec_s - 1]);
        $decrypted = substr($encryptedData, 0, -$padding);

        mcrypt_generic_deinit($module);
        mcrypt_module_close($module);
        if (!$decrypted) {
            throw new \Exception("Decrypt Error,Please Check SecretKey");
        }

        return $decrypted;
    }
}
